Neovascular Glaucoma

Transcription

1 Ophthalmic Deliberations ISSN Neovascular Glaucoma Sonal Dangda, Harsh Kumar, Kirti Singh, Tanuj Dada, Suneeta Dubey, Sirisha Senthil, Arun Narayanaswamy, Avnindra Gupta Harsh Kumar MD, DNB Senior Consultant & Head (Glaucoma services) Centre For Sight, New Delhi, India Sonal Dangda MS, DNB Associate Consultant (Glaucoma), Centre For Sight, New Delhi, india Tanuj Dada MD Professor, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India Sirisha Senthil MS, FRCS Consultant, VST Centre for Glaucoma, LV Prasad Eye Institute, Hyderabad, India Avnindra Gupta MS Senior Consultant (Retina), Centre For Sight, New Delhi Kirti Singh MD, DNB, FRCS Director Professor, Guru Nanak Eye Centre, Maulana Azad Medical College, New Delhi, India Suneeta Dubey MS Consultant & Head (Glaucoma services), Dr. Shroff s Charity Eye Hospital, New Delhi, India Arun Narayanaswamy DNB, MMed Adjunct Faculty (Glaucoma), Singapore Eye Research Institute, Singapore Secondary glaucomas have always been difficult to deal with, especially demanding the expertise of various ophthalmic subspecialities. Neovascular Glaucoma (NVG) is one such entity; which presents in dramatic forms, is difficult to treat and gives little time to react. With modern lifestyle there is trend towards rise of lifestyle diseases but also available are modern technologies to treat the same. What is important is a timely diagnosis and intervention. With the ever changing trends, wider choices, and a race against time, it sometimes gets perplexing as to what to attempt when. As treatment of NVG requires a close co-ordination between two subspecialities i.e. glaucoma and retina, discussion is incomplete without perspective from both. We have seven eminent faculties from various prestigious institutions, dealing with patients across a wide socioeconomic spectrum, to discuss their experiences and protocol pertaining to the varied spectrum of presentation of neovascular glaucoma. Sonal Dangda - Q. What are the common etiologies of NVG in your practice group? Harsh Kumar: The commonest cause of NVG in my practice by far is diabetic retinopathy. Second common cause is venous occlusion. Beyond this one gets patients with inflammation, ocular surgery and ocular ischemia; though rare causes like tumours can also be present. Kirti Singh: The two most common causes of neovascular glaucoma in my practice are diabetic retinopathy and venous occlusions. We also see the disease in patients with chronic uveitis and old retinal detachment. Tanuj Dada: Proliferative Diabetic Retinopathy (PDR) and Central Retinal Vein Occlusion (CRVO) are the most common etiologies; others being Ocular Ischemic Syndrome, Hemiretinal & Branch Retinal Vein Occlusions (BRVO), chronic uveitis, tumours etc. We also see cases with chronic primary angle closure glaucoma (PACG) developing vascular occlusions followed by NVG. It is important to understand that this disease develops partly due to our negligence as we fail to recognize patients at high risk of developing NVG and thus treating them at an early stage so as to prevent anterior segment neovascularization. Additionally gonioscopy and undilated pupillary examination are rarely performed or correctly interpreted in PDR/CRVO patients and early neovascularization of angle/ iris (NVA/NVI) is often missed - a stage where the disease could have been prevented. Suneeta Dubey: The two most common etiologies which we regularly encounter are PDR and ischemic CRVO. Other less common ones are trauma, long standing retinal detachments & chronic uveitis. Del J Ophthalmol - Vol 26 No: 2 October-December

2 E-ISSN Ophthalmic Deliberations Sirisha Senthil: PDR and CRVO. Arun Narayanaswamy: 1. Proliferative Diabetic Retinopathy 2. Central & Hemi-central Vascular Occlusions 3. Ocular Ischemic Syndrome Avnindra Gupta: Common causes of NVG in my practice are - 1) Central & Hemi-central Vascular Occlusions 2) PDR 3) Patients with occlusive vasculitis like Eales disease, Herpes Simplex & Zoster vasculitis also lands up in NVG 4) Patients with large area of retinectomy develop NVI but these patient do not land up with increased IOP. Summary (Sonal Dangda): The common etiologies of NVG are PDR & retinal vascular occlusions i.e CRVO, Hemiretinal and Branch Retinal Vein Occlusions (HRVO/BRVO) & Ocular Ischaemic Syndrome. Other less commonly encountered conditions are chronic uveitis, long standing retinal detachments, trauma, tumours, occlusive vasculitis and chronic angle closure glaucoma developing vascular occlusions. 1,2 Sonal Dangda - Q. Keeping in mind the two most common etiologies, is there a difference in treating NVG due to Proliferative Diabetic Retinopathy (PDR) & that accompanying vascular occlusions (like CRVO)? Harsh Kumar: Patients with diabetic retinopathy are a more compromised population and always more difficult to treat. Drugs like glycerol and acetazolamide need to be withheld in some in view of compromised kidneys. Also blood sugar control is often poor and may lead to undue delays in surgery which can worsen the existing situation. The ability to judge the disc for deciding the progression and the need for intervention is also hampered in diabetics due to media problems in PDR like vitreous haemorrhage. However the overall treatment in both situations depends on ablation of the avascular retina in order to prevent formation of the angiogenesis factors and control of the intraocular pressure (IOP) by medications or surgery. Kirti Singh: The treatment regimen for NVG resulting from either condition is intravitreal anti-vegf (Vascular Endothelial Growth Factor) followed by Panretinal Photocoagulation (PRP), with anterior retinal cryopexy (ARC) being reserved in conditions where fundus visibility or visual prognosis is poor. The anti-vegf injections may need to be repeated for complete regression of rubeosis; their use reduces retinal edema as well as laser power required for effective PRP. In diabetic retinopathy concomitant ocular conditions like lens status & prior vitrectomy compound the picture. Wherever feasible prompt PRP alone or combined with endo-photocoagulation as part of pars plana vitrectomy (PPV) should be done. Associated macular edema needs to be differentiated as ischemic or non-ischemic in origin. For the ischemic edema, anti-vegf therapy is not given, instead intravitreal steroids are to be used and followed by PRP depending on the extent of retinopathy. For both DR and CRVO strict metabolic control of underlying pathology like diabetes and hyperlipidaemia is a must for any treatment to be effective. Tanuj Dada: The basics of treatment of NVG remain the same in both cases (Systemic control of Diabetes/ Hypertension, PRP, Anti-VEGF, topical medications to control IOP, trabeculectomy, drainage devices and cyclophotocoagulation in that order). However in PDR with vitreous haemorrhage with NVG, a Pars Plana Vitrectomy with Endolaser is the preferred option. Managing NVG is based on 4 essential principles: 1. Regression of abnormal new vessels. 2. Reduction of ischemic drive producing vascular endothelial growth factor (VEGF). 3. Reduction of inflammation. 4. Reduction of IOP with medications initially followed by surgery when inflammation and new vessels have regressed. Currently the best outcomes can be achieved in all cases presenting with NVG by an initial single intravitreal injection of anti-vegf (i.e. Bevacizumab 1.25 mg) to regress new blood vessels, decrease vascular permeability and subsequently inflammation, followed by full scatter pan retinal photocoagulation preferably with Laser Indirect Ophthalmoscope (LIO) so that the retinal periphery can also be lasered. The IOP is lowered with all possible medications (except pilocarpine and prostaglandin analogues and glycerol in Diabetics) and a trabeculectomy/tube is performed in a quiet eye with regressed neovascularization. There may be some merit in giving a higher (2.0 mg) dose of Bevacizumab (Avastin) in Neovascular glaucoma to achieve a more rapid and prolonged effect although further studies are required to substantiate this hypothesis. The IOP may rise after intravitreal injection due to a volume effect and an anterior chamber (AC) paracentesis may be required. Suneeta Dubey: NVG due to PDR & CRVO is basically due to the excessive amounts of VEGF being secreted by the ischemic retina. The management is pretty much similar in both the conditions and has two main components. The foremost treatment plan is to control the IOP and the other component which is most critical for long term outcome is reduction of the ischemic drive that induces formation of new blood vessels. The neovascularization process needs to be interrupted by injecting anti-vegf agents like Bevacizumab (Avastin) or Ranibizumab (Lucentis/ Accentrix) followed by laser photocoagulation or anterior retinal cryotherapy depending on the media clarity. Sirisha Senthil: Although the etiologies may be different, NVG is a potentially blinding disease and needs utmost care and attention. Detailed medical history, pupillary reaction to rule out Relative Afferent Pupillary Defect (RAPD) in CRVO, early NVI at the pupillary margin, gonioscopy for NVA (in an undilated state), status of the fellow eye, etiology of neovascularization, systemic causative factors and their control are important in early and appropriate diagnosis and treatment. The management in both the conditions is to treat the ischemic retina with PRP ± anti-vegf and control the IOP aggressively. The management is a combined effort 139

3 Ophthalmic Deliberations ISSN from retina and glaucoma specialists and needs closer monitoring. Arun Narayanaswamy: The process of managing the glaucoma does not change due to etiology. The main relevance of identifying cause is to simultaneously address the underlying ocular and systemic conditions. Appropriate co-management with retinal experts and physicians is of paramount importance. Avnindra Gupta: CRVO is a disease of extreme periphery so ablation should be done from mid-periphery to ora serrata. You can spare central area. In PDR, Pan Retinal Photocoagulation should extend 2 DD superior and inferior from vascular arcades nasally and 2 DD from centre of the fovea to ora serrata temporally. It is very important to ablate the area beyond equator in NVG with almost contiguous spots to achieve the desired result i.e. regression of new vessels. In cases where ablation of the peripheral retina is difficult even with a LIO, combined Anterior Retinal Cryopexy might have to be considered. Summary (Sonal Dangda): Although etiology may vary but the pathophysiology for growth of new vessels is the same. It is important to reduce the ischaemic drive by ablating the hypoxic retina thereby decreasing production of Vascular Endothelial Growth Factor (VEGF). It is pertinent to aggressively treat the Intraocular Pressure (IOP). Detection of neovascularisation of iris (NVI) (Figure 1) & angle (NVA) should be done at the earliest so as to prevent formation of fibrovascular membrane which ultimately would close the anterior chamber angle. 2 The fellow eye and systemic status needs to be simultaneously looked into. Figure 1: Slit lamp examination showing NVI Sonal Dangda: A few case scenarios relating to the varied clinical spectrum of NVG are presented below: Case A:- 75 Years Male, B/E Early Immature Senile Cataract (IMSC) presented with L/E CRVO with NVI; BCVA 6/60-, IOP upto 35mmHg; Gonioscopically open upto posterior trabecular meshwork >180 degree (Figure 2); Optic Disc showing mild hyperaemia without any glaucomatous cupping. Q. What would be your choice of medications at this stage - preferably oral or topical? Harsh Kumar: Dorzolamide/Brinzolamide thrice a day alongwith combination of Timolol and Brimonidine twice Figure 2: Gonioscopic picture showing open angles daily would be the preferable choice at this stage. Care to be taken in ruling out asthma, chronic obstructive airway disease or heart blocks which are common at this age and will preclude Timolol use. We should be comfortable with an IOP around 20. If further lowering is required, one can split the combination therapy to Brimonidine three times and Timolol twice a day. There seems to be no need for oral medications at this IOP and age. Kirti Singh: The IOP needs to be controlled with both systemic and topical medications; prostaglandin analogues being avoided as concomitant macular edema is common in this scenario. Tanuj Dada: A combination of topical drugs i.e. betablocker, alpha-agonists and carbonic anhydrase inhibitor (CAI) would be my choice. Topical CAIs might need to be substituted with oral acetazolamide in cases where IOP control is difficult but only after ruling out systemic contraindications. Give intravitreal Avastin followed by PRP. If cataract does not allow PRP, give Avastin perform cataract surgery and then do non-contact PRP with LIO. Suneeta Dubey: My choice of medications at this stage would be topical aqueous suppressants - preferably a combination of CAI and beta-blocker if IOP is not controlled with a single drug. Oral administration of CAIs can be considered in patients with uncontrolled IOP on topical drops, and those who can tolerate this class of medications. Sirisha Senthil: Topical beta-blockers with alpha-agonist combination along with oral CAI, when needed, are the medications of choice. In the presence of persistent NVI with open angles, treat the retinal ischemia aggressively so that the angle can be salvaged. Arun Narayanaswamy: The therapeutic strategy I would adopt is an aggressive combination of topical aqueous suppressants (beta-blockers, alpha-2 agonists, and CAIs), steroids and cycloplegics. Systemic CAI would be an option Del J Ophthalmol - Vol 26 No: 2 October-December

4 E-ISSN Ophthalmic Deliberations if response to topical agents is inadequate and there are no systemic contraindications for the same. The patient profile that present with these ocular conditions should be screened for any renal compromise before considering acetazolamide and also be periodically monitored for electrolyte imbalance when on acetazolamide therapy. Summary (Sonal Dangda): Topical aqueous suppressants (betablocker, alpha-agonist and carbonic anhydrase inhibitors), in combination where needed, are the initial choice of therapy. It is also important to judiciously use steroids and cycloplegics for inflammation control. Oral/systemic medications can be considered in cases not responding to above after ruling out the said contraindications. Sonal Dangda - Q. Would you consider adding Prostaglandin Analogues (PGAs) in cases not responding to topical aqueous suppressants? Harsh Kumar: PGAs can be added according to need but keep them as the last choice because they tend to cause inflammation. Keep a watch on visual acuity, which if tends to decrease would warrant PGA withdrawal. Kirti Singh: The use of PGAs are equivocal because they can be pro-inflammatory, but they re often used anyway, trying to prevent the situation from becoming worse. Besides, in later stages access to uveoscleral route is compromised from angle closure. Tanuj Dada: PGAs should be avoided as they tend to increase inflammation and there is a compromised access to the uveoscleral pathway. There can be worsening of macular oedema with their use. Also the success of filtration surgery decreases with aggravation of inflammation. Suneeta Dubey: Since in this patient there is no synechial closure, PGAs can be considered if IOP is not controlled with aqueous suppressants. However, the condition is associated with marked inflammation and the patient should be kept under topical steroid cover and cycloplegics. Sirisha Senthil: Yes we can consider PGAs in desperate situations if nothing else is of help or as a temporary measure before surgery; especially in situations where patient cannot tolerate oral CAI or is allergic to other topical medications. Arun Narayanaswamy: I generally avoid PGAs because of their propensity to increase existing inflammation and theoretically the pathway (Uveoscleral) for them to act effectively is compromised in eyes with NVG. Avnindra Gupta: PGAs can be started in patients with CRVO as the pathogenesis of macular edema is non-inflammatory i.e. venous stasis resulting in exudation of serous fluid from the capillaries. In such non-inflammatory cases, macular edema is not going to worsen with PGAs; which will have to be controlled with VEGF inhibitor. PGAs are a relative contraindication in cases with inflammation. Summary (Sonal Dangda): PG analogues need to be individualised. They may have relevance in cases where angle is still open & uveoscleral route of aqueous drainage is accessible but only as a last resort when topical aqueous suppressants are inadequate & systemic medications can t be prescribed. Benefits, however, need to be weighed against risks of increased inflammation which may compromise a definitive glaucoma filtration procedure later on. Sonal Dangda - Q. Post Panretinal Photocoagulation (PRP) how long should you comfortably wait for NVI to regress? How would you follow-up this patient? Harsh Kumar: If IOP is well controlled then it will be the retina specialist s call to add therapy. If IOP is not controlled one can check if they can put anti-vegf and then do surgery after regression of NVI in 2-3 days. Keep a regular check for IOP and disc and modify medications accordingly. Kirti Singh: The response to PRP starts within 1-2 week and takes 4-6 weeks for complete effect. Once the rubeotic vessels regress gonioscopy needs to be repeated and if angle zipping has not started the patient can be kept under follow up. However a word of caution, in apparently open angles in patients with regressed NVA on gonioscopy transparent residual ghost vessel bodies persist and can go on to form synechial membranes with closed angles that are recalcitrant to medical treatment and require glaucoma surgery. Thus, close observation of regressed NVA including regular gonioscopy in all quadrants is a must for treating incipient glaucoma prior to significant optic nerve damage. If at any time glaucomatous damage is evident or pressure starts rising trabeculectomy/tube shunt should be performed. Follow up has to be lifelong and in addition to monitoring of glaucoma, the initiating disease process also has to be monitored eg. diabetic retinopathy. Good glycaemic control and stringent lipid control for diabetics and patients with vascular occlusions is mandatory to prevent recurrence of the rubeosis. Tanuj Dada: After complete PRP has been done alone without Avastin, NVI will regress in 4-6 weeks. The patient can be maintained on 2 weekly follow up till complete regression has occurred and the IOP has to be controlled with medications in this period. However it is best to do a combo therapy of Avastin and PRP to get the best outcome and early regression of NVI. Suneeta Dubey: I would wait for at least 2 weeks for the laser to destroy the ischemic retina & to reduce the VEGF load & subsequently for the NVI to regress. I would follow up the patient till the NVI have totally regressed and the IOP is well under control. Sirisha Senthil: Ideally the laser response takes 3-4 weeks, and the NVI may regress during that time. Arun Narayanaswamy: Our protocol is to combine PRP with intravitreal anti-vegf injection and wait for 2-3 weeks to consider further intervention. I would follow up this patient on a weekly basis for the first month in order to titrate the therapy, follow up on the status of NVI and NVA & assess the need for further intervention. 141

5 Ophthalmic Deliberations ISSN Avnindra Gupta: Regression of NVI starts from 2 weeks & takes 6 weeks after completion of the peripheral ablation. Summary (Sonal Dangda): Post PRP regression of NVI starts by 2 weeks and takes around 4-6 weeks for complete effect. 4 Close monitoring of IOP and systemic status is required initially along with repeated gonioscopy to assess status of angle neovascularisation and subsequent synechial closure. 5 Follow-up has to be regular; need to watch out for any recurrences in future. Sonal Dangda: Case B:- 58 Years Male CRVO L/E and presents with florid NVI and 360 degree PAS; IOP 48mmHg not controlled on topical aqueous suppressants and patient non-compliant with oral acetazolamide; edematous cornea precluding clear view of posterior segment (Figure 3); BCVA 3/60 PR accurate. Q. What would be your further course of management, knowing that PRP might be difficult in this case? Is there a role of anti-vegf? Figure 3: Fundus picture showing CRVO through hazy media Harsh Kumar: At these pressures no topical medication is going to be effective. Since patient is non-compliant to oral drugs adding Glycerol is unlikely to help. I would like to give intravenous mannitol after which cornea is likely to clear to some extent when one can examine the extent of NVI and the depth of the chamber. I would then prefer to go for a valve surgery immediately. Giving anti-vegf may not benefit in a valve but if the surgeon only has experience in trabeculectomy then one would have to give this injection and wait for 2-3 days for NVI to regress when one can undertake a trabeculectomy with Mitomycin C (MMC). Kirti Singh: In these cases with cloudy media medical therapy along with systemic Mannitol under supervision is initiated for IOP control. This is followed by anti-vegf therapy which can be repeated. Administration of anti-vegf drugs usually lead to rapid regression of NVI, associated inflammation and glaucoma which can successfully restore corneal clarity. Once that occurs a definitive PRP should be done as a more permanent reduction of the ischemic angiogenic stimulus. It needs to be kept in mind that sometimes intravitreal injections of anti-vegf agents themselves result in marked acute IOP elevation, necessitating either pre- or postinjection AC paracentesis. Tanuj Dada: For immediate IOP lowering give hyperosmotic agents (Mannitol, Glycerol) along with topical medications. Do a B scan ultrasonography (USG B scan) if media is very hazy and then give intravitreal Avastin with AC paracentesis. If the IOP goes down and cornea clears, follow up with PRP. As there is 360 degree PAS the patient will require glaucoma surgery. Suneeta Dubey: Yes. Anti-VEGFs have a definite role to play in this case. They help in regressing the NVI. Since the patient is not responding to medical management because of synechial angle closure, glaucoma surgery needs to be done to reduce the IOP, following which laser can be done in these cases. Sirisha Senthil: Consider anti-vegf with combined anterior retinal cryopexy and diode laser cyclophotocoagulation. Arun Narayanaswamy: My approach in this category of patients is to co-manage with a retinal sub-specialist and do a limited diode cycloablation (inferior 180 degrees) combined with a retinal cryoablation/diopexy. Anti-VEGF definitely has an adjunctive role and can be administered at the same sitting or shortly thereafter. There would be a need to perform an anterior chamber paracentesis prior to intravitreal injection. Points to note would be to ensure strict asepsis, avoid sudden AC decompression and co-manage with retinal colleagues. Avnindra Gupta: In the above situation where patient is on maximal medication and posterior segment visualization is poor, I will prefer to give anti-vegf under mannitol. Doing paracentesis in patients of NVG is risky as sudden lowering of IOP can result in intracameral bleed. This should be followed by glaucoma surgery either AGV or trabeculectomy with MMC. Summary (Sonal Dangda): Patients presenting in this manner are always a nightmare for the treating surgeons and often a dilemma as well. However the basic approach to treatment remains the same i.e. systemic hyperosmotic agents (intravenous mannitol and oral glycerol after ruling out systemic contraindications) for immediate reduction of IOP which will have to be followed by definitive treatment for control of ischaemic stimulus i.e. PRP if cornea clears enough. 5 Else intravitreal anti-vegf needs to be considered for early regression of NVI 6 followed by glaucoma surgery for IOP control. PRP then has to be completed post-op once the media clears. 7 Limited inferior Diode laser cyclophotocoagulation (DLCP) alongwith Anterior Reitnal Cryopexy is also an option. 8 Sonal Dangda - Q. What should be the ideal time interval after intravitreal anti-vegf within which glaucoma Del J Ophthalmol - Vol 26 No: 2 October-December

6 E-ISSN Ophthalmic Deliberations surgery can be attempted? Is there a role of intracameral anti-vegf to expedite the NVI regression? What would be the appropriate dose? Harsh Kumar: The NVI may disappear as quickly as in a day or two and we can then plan surgery after two to three days of anti-vegf injection. Intracameral injection of avastin is given in the same dose as intravitreal (i.e mg in 0.05 ml) through a 30 gauge needle directly into the anterior chamber has been reported to show dramatic resolution of the neovascularisation in as early as 36 hours but few have also reported a duration upto 16 days. However as the pathology is in the posterior segment, it is advisable to add intravitreal injections. Kirti Singh: Administration of anti-vegf agents preoperatively (within one week of surgery) reduces complications like bleeding, by causing rapid regression of new vessels (which tend to be more fragile and leaky). The pressure lowering effect of these agents starts 1 week after the injection and remains for approximately 3-4 weeks. Therefore definitive glaucoma filtering surgery should be performed with 1 3 weeks of the injection. When anatomic landmarks are unclear or surgeon is more comfortable with anterior segment surgery intracameral injections also can be used as an effective alternative to reduce NVI/NVA. These intracameral injections may be given simultaneously with trabeculectomy/tube shunt procedures. However wash out is more rapid for intracameral anti-vegf and intravitreal is the optimum modality of delivering this drug. A dose of 1.25 mg of bevacizumab in 0.05ml has been mostly used as intravitreal injection. The ideal dose of intracameral injections for NVG is however unknown with one study finding no difference when 1.25 vs 2.5 mg intracameral bevacizumab was injected during Trabeculectomy with MMC. Tanuj Dada: Perform surgery between 72 hrs 1 week after anti-vegf if PRP is not possible. Avastin (1.25 mg) should be given intravitreal as the VEGF is released from the retina and you require the drug in the vitreous. Intracameral Avastin may be used if there is a retinal detachment and as an additional treatment prior to trabeculectomy. Suneeta Dubey: Glaucoma surgery can be attempted one week following treatment with anti-vegf agents. Intracameral anti-vegf helps in faster regression of the new vessels; 1.25 mg in 0.05 ml of Avastin or 0.3 mg in 0.05 ml of Lucentis can be safely injected in the anterior chamber after careful paracentesis. Sudden hypotony needs to be avoided to prevent bleeding from the new vessels into the anterior chamber. Sirisha Senthil: With the anti-vegf treatment the NVI tend to regress as early as 24 hours, we can intervene surgically for glaucoma in a week. Since the effect of anti-vegf is short lived, surgeon should complete definitive PRP after the IOP is controlled and cornea clears (within one month). Although intracameral anti-vegf can be given (dose is similar to intravitreal 1.25mg in 0.05cc), since the ischemic pathology is in the posterior segment, it is ideally given intravitreally. When given intravitreally, the drug can reach the anterior segment but may not be so vice versa. Also, when given intracamerally during trabeculectomy, the drug may escape subconjunctivally rather than stay in the anterior chamber. In cases with only anterior segment NVI like in Ocular ischemic syndrome and Fuch s uveitis with NVG, one can consider anti-vegf intracamerally. Arun Narayanaswamy: Regression of NVI after intravitreal anti-vegf can be noted in most eyes as early as the first week and in some cases even earlier. It would be ideal to wait for 2-3 weeks to ensure a quiet eye with a suppressed neovascular process. Though intracameral injections have been reported to be effective, evidence of it being more expeditious is lacking. I prefer intravitreal anti-vegf as the pathology is primarily in the posterior segment and injecting intravitreally has the potential to ensure a prolonged effect and also take care of co-existing issues such as macular oedema. I use a dose of 1.25mg /0.05ml of bevacizumab and most practice protocols recommend the same. Avnindra Gupta: Regression of NVI starts within 12 hrs of anti-vegf injection however it starts to reappear after 15 days. So the ideal time for surgery is between day 1 to 10 days post injection. Effect of intracameral anti-vegf is same as intravitreal. There is no proven difference between the two procedures. Dose is also the same as intravitreal i.e. 1.25mg/0.05cc. Summary (Sonal Dangda): Intravitreal injection of anti- VEGF leads to early regression of NVI; effect starts within 24 hours however it is short-lived. 9,10 Surgical intervention can be considered within a week of above. 6 As regards role of intracameral anti-vegf, the effect is similar to intravitreal; literature does not report any additional advantages. Dose is also same as intravitreal (1.25mg/0.05ml Bevacizumab/Avastin, 0.3mg/0.05ml Ranibizumab/Lucentis). 11 Sonal Dangda - Q. Does Anterior Retinal Cryoablation (ARC) have a role in the age of anti-vegf? Harsh Kumar: In case one cannot visualise the posterior segment, like in corneal opacity or vitreous haemorrhage, anterior retinal cryotherapy will be required to tackle the NVI. Sometimes even after PRP we find that the NVI has not regressed completely; add ARC in such cases to handle the most peripheral regions. Kirti Singh: ARC was strongly recommended in the past, especially in eyes with media opacities precluding PRP and as a preliminary procedure for filtering surgery or drainage implant surgery. Following ARC, in one study, pain relief with dramatic regression of AC inflammatory reaction was observed in 95% of patients, regression of NVI in 93.5% and IOP control achieved in 83% eyes. At present, its role is limited to eyes with opaque media due to vitreous haemorrhage or dense cataract as a preliminary procedure to glaucoma surgery with co-existing contraindications for anti-vegf. 143

7 Ophthalmic Deliberations ISSN Tanuj Dada: If you are not able to ablate the retinal periphery with a slit lamp delivery system and do not have an indirect laser system, an ARC done under visualization is helpful. Additionally in eyes with poor visual potential, small pupil, and hazy media ARC may be performed. Suneeta Dubey: ARC does have a role in the present era of anti-vegf for treatment of NVG. It is useful in cases where the fundus is not visible due to vitreous haemorrhage, corneal haze and stiff non dilating pupils, or when anti- VEGFs are not available. Sirisha Senthil: Yes it does and is usually combined with DLCP especially in eyes with vitreous haemorrhage where we know that the retinal laser may have to be delayed for a few weeks. Arun Narayanaswamy: Anterior Retinal ablation (either by Cryo or Diopexy) has a definite role in the management of NVG. These are typically employed when Slit-Lamp / LIO delivery of laser is not possible due to a poor view of the posterior segment. The anti-vegf agents are useful adjuncts but their effects are transient. Avnindra Gupta: Limitation with anti-vegf is that its effect is transient and hence it is not cost-effective for treatment of NVG. Permanent solution is ablation of the ischemic retina which ultimately is the source of VEGF. Ideally we try to ablate the peripheral retina with laser but in many situations retinal periphery cannot be visualized (eg. edge effect of intraocular lens). In such situations, ARC is an option to be considered. Summary (Sonal Dangda): In the era of anti-vegf, ARC may have taken a backseat but it is still particularly useful in cases with compromised posterior segment view (like in vitreous haemorrhage, corneal haze/opacity, stiff non-dilating pupils, dense cataract) and anti-vegfs are either not available or affordability is an issue. 12,13 Also in cases where retinal periphery cannot be visualized, there is no access to LIO, and in eyes with poor visual potential. 8 Sonal Dangda: Case C :- 70 Years one eyed patient suffering from Diabetes Mellitus (DM) & Chronic Kidney Disease (CKD) presents with PDR (no H/O previous PRP) and Florid NVI R/E; BCVA 2/60 PR accurate; IOP 45mmHg; Gonioscopy showing >270 closed angles OU with NVA (Figure 4). Q. What would be the ideal time interval between PRP and Glaucoma Surgery? In such scenarios, is it preferable to wait for PRP completion and NVI to regress completely before any surgical intervention is done? Would your management change knowing that this patient is one eyed? Harsh Kumar: There is no ideal time interval between completion of PRP and glaucoma surgery. The aim of PRP is to abolish the source of the angiogenesis factor and it thus leads to a gradual fading of NVI and resolution of NVG. Figure 4: Gonioscopy showing >270 0 closed angle Though we know that it takes anywhere between 2 to 6 weeks for PRP to be effective, we need to weigh the ability of the optic nerve to sustain itself at the maximum tolerable anti-glaucoma medications for this time frame. If at any time we feel that the optic disc is not able to tolerate high pressures take the patient for glaucoma surgery. Another point to consider is that there is no perfect way to determine if the PRP carried out is adequate. It will be over a period of time that one realises that inspite of doing a supposedly adequate ablation, the NVI still persists; augment with further PRP or ARC in such cases. In most patients, this extended time frame may not allow for the glaucoma surgery to be postponed. In the current scenario with the pressures being above 40 and the eye being the only seeing eye, we will have to intervene early with surgery. Kirti Singh: One can consider glaucoma surgery within 2-3 weeks of the injection and initial session of PRP. Although ideally preference should be given to complete regression of vessels as this patient with kidney disease cannot be given many systemic anti-glaucoma drugs if hyphema with secondary glaucoma were to happen once surgery is done in inadequately regressed new vessels. However, an IOP of 45mmHg in a one-eyed patient with expected disc damage would not allow an extended waiting period, therefore one must operate (preferably a tube in this situation) under anti-vegf cover; it may not be wise to wait for complete resolution of all vessels. Tanuj Dada: An IOP of 45mmHg in a one eyed patient with contraindication to hyper-osmotics or acetazolamide use, needs to be tackled in a specific and urgent manner. No point in performing glaucoma surgery with active NVI. There will be active bleed and the patient will develop a sudden visual loss due to your intervention. Furthermore the surgery will fail very soon. That is why I recommend an unconventional approach, which is, 25 G core vitrectomy to soften the eye followed by Avastin. Take the patient to the operation theatre, do a 25 G limited core vitrectomy to reduce IOP and give intravitreal Avastin. Follow up with PRP (full scatter including retinal periphery). Stabilize blood sugars, urea, creatinine with dialysis and appropriate medical management by nephrologist & endocrinologist and then (do prayer and explain bad prognosis!) perform Trabeculectomy with Mitomycin-C. Suneeta Dubey: Ideal time interval between PRP and glaucoma surgery would be about 7-14 days. However, in one eyed cases it is better to be slightly aggressive with Del J Ophthalmol - Vol 26 No: 2 October-December

8 E-ISSN Ophthalmic Deliberations your treatment plan. I would give these patients anti-vegf agents both intravitreal & intracameral and operate this patient within a week time to control his IOP. Sirisha Senthil: Ideal time interval would be 2-4 weeks based on the IOP control and status of new vessels. However, since regression of new vessels takes time after retinal laser, one can plan anti-vegf along with PRP and intervene surgically for glaucoma at the earliest. Arun Narayanaswamy: Ideal time would be about 2-3 weeks after PRP however this has to individualized based on the clinical needs. With the availability of anti-vegf as adjuncts, this period can be shortened to 1 week depending on the response and regression of neovascularisation. Aggressive topical aqueous suppressants, steroids and cycloplegics would help buy time and quieten down the eye prior to surgery. A balanced approach with regard to timing is required in such scenarios. Invasive procedures done in haste have a significant risk of blinding complications. If raised IOP despite maximal therapy is of concern, a limited diode cycloablation (inferior 180 degrees) could be considered to bring down the IOP and a more definitive procedure can be considered at a later stage. Avnindra Gupta: In such a patient, if we wait for regression of NVI following PRP patient will lose vision due to high IOP. So a filtering surgery is a must in these cases, followed by PRP. There can be two scenarios in this. One with a flat NVE or surface neovascularisation; in which case I will give anti-vegf and request our colleague to do a filtering surgery either AGV or Trabeculectomy and then I will start with PRP on day 1 (provided the cornea is clear) with LIO and try to finish it by 15 days. Only thing to watch out for is a choroidal detachment; so divide your PRP in multiple sittings with not more than 400 spots in single sitting. The second scenario is when there is a fibro-vascular proliferation; here intravitreal anti-vegf injection is a relative contraindication. In these situations first a filtering surgery should be done followed by PRP. Summary (Sonal Dangda): Such scenarios, encountered often, across all socio-economic spectrum, compounded by the fact that the patient is one-eyed, are a tight rope-walk for the surgeon. Timing of glaucoma surgery in relation to PRP has to be individualised according to the patient s parameters; points to consider include IOP control, state of the angle and new vessels, optic nerve health, fellow eye and also the systemic status. Both schools of thought early surgical intervention under anti-vegf cover followed by PRP post-operatively or medically manage IOP (can also consider limited Diode Cycloablation) along with PRP and wait for NVI to regress have equal and relevant limitations and advantages. 3,6,7,14 Decision ultimately rests with what the surgeon is confident about. Sonal Dangda - Q. What is the preferable choice of glaucoma surgery in this patient Trabeculectomy with anti-fibrotics or Glaucoma Drainage Devices (GDDs)? Knowing that there is a high risk of failure should GDDs be the first line in all cases? Harsh Kumar: This question is good for theoretical consideration but the hard fact is that there are very few surgeons who are adept at implanting the valve but there are hundreds of general ophthalmologists who are faced with this scenario frequently. They may not be able to send the patient for specialist care as most of these patients can ill afford to visit a far-away clinic due to financial problems. Thus for majority of our friends the choice is only between doing a Trabeculectomy with MMC or referring the patient. If there is no NVI one could get away by doing a Trabeculectomy but with any residual NVI one would prefer to do a valve. So in a peripheral set up a surgeon could give an anti-vegf, both intravitreal and intracameral, and wait for 2-3 days. The moment one feels that NVI is gone they could take up the patient for Trabeculectomy with MMC. The GDDs do reasonably well in experienced hands and when a person has adequate exposure then this may be the first choice in managing NVG. Kirti Singh: In this one eyed patient, GDD would be the preferred surgery but Trabeculectomy with anti-fibrotics is also a viable option. Surgeon s skill and experience with both/either operation would dictate the choice. NVG is a known risk factor for failure of trabeculectomy; with failure rates ranging up to 80% and an increased incidence of encapsulated blebs, the possibility of a repeat trabeculectomy should be explained to the patient. If this patient is a pseudophakic or had a past history of vitrectomy, then GDD scores over trabeculectomy because scleral collapse & hypotony followed by a hypertensive bleb phase are common scenarios after trabeculectomy in such eyes. Anti-VEGF injections combined with trabeculectomy/ tube shunt improve the surgical outcome by controlling wound healing. In case, the patient is phakic and/or has a shallow anterior chamber, Trabeculectomy with anti-fibrotics should be considered. Although GDDs have gained popularity in the surgical treatment of NVG as their success is less dependent on control of intraocular inflammation and on wound healing, but are not a panacea as IOP control usually diminishes from 60 to 90% in the first year to 10 to 46 % at five years. Also hypertensive phase in tube shunts needs to be guarded against and treated accordingly. Tanuj Dada: Both Trabeculectomy and GDD have poor long term outcomes in NVG. We usually perform Trabeculectomy with sub-scleral and subconjunctival MMC (0.04%) as the initial surgery. GDDs can be used if the trabeculectomy fails, or as primary surgery if there is extensive conjunctival scarring or in eyes with NVG and cataract as a combined surgery (Phaco- GDD) post Avastin injection. The reason why I use GDDs with caution is that they have a higher risk of sight threatening complications, like hypotony, phthisis etc. Also GDDs have a higher risk of corneal decompensation. Patients often develop large cysts due to encapsulation which is resistant to treatment. They are more costly and the cost-benefit ratio is lower than Trabeculectomy as the 3-5 year outcomes are similar. GDDs require more surgical expertise and more 145

9 Ophthalmic Deliberations ISSN patient follow up visits. With use of new non-valved drainage devices like Aurolab Aqueous Drainage Implant (AADI), the IOP cannot be lowered upto 6-8mmHg post-surgery which puts the patient at an additional risk. The best case scenario is a pseudophakic NVG eye with conjunctival scarring, in which, I perform an Ahmed Glaucoma Valve (AGV) implant with tube placement under the iris & above the IOL i.e. the ciliary sulcus location, for optimal results. This significantly decreases the risk of corneal complications. Another option is to combine 23 G Pars Plana Vitrectomy + endolaser in a diabetic NVG with a pars plana GDD. Suneeta Dubey: Glaucoma drainage device would be my preferred mode of surgery in this patient as the chances of failure of Trabeculectomy are very high due to excessive inflammation associated with the condition. In my experience GDD has a better prognosis and should be used as a primary procedure, in all cases, as their success is less dependent on control of intraocular inflammation and the failure of a filtering bleb. Sirisha Senthil: In the absence of conjunctival scarring, Trabeculectomy with MMC has a role to play. I don t think GDDs should be the first line in all cases. Trabeculectomy with MMC is still my first choice unless patient has had multiple previous intraocular surgeries and has scarred conjunctiva or has other risk factors like aphakia etc. Arun Narayanaswamy: My choice of surgery in NVG is a valved GDD. There is a lack of compelling evidence on the eventual superiority of GDD over Mitomycin C modulated Trabeculectomy. The choice should depend on the practice setting, surgeon comfort and availability of resources. I lean towards using a tube as my preferred procedure as the eye with NVG is significantly inflamed and with GDD one does not have to manipulate a vascular iris. Summary (Sonal Dangda): Although GDDs are vast gaining popularity, Trabeculectomy with anti-fibrotics (MMC) still remains a viable choice in many circumstances GDDs can be specifically considered in cases with extensive conjunctival scarring, aphakia, pseudophakia, etc. Sonal Dangda - Q. Is there a role of Diode Laser Cyclophotocoagulation (DLCP) in seeing eyes with high IOP unconducive for immediate surgical intervention? Harsh Kumar: DLCP in a seeing eye is being carried out with greater success nowadays; done in a situation where the other two surgeries are contraindicated due to certain reasons. One has to do this in a graded fashion so as not to cause phthisis, a dreaded complication. One could possibly tackle a quadrant or 100 degrees and repeat the same after 6 weeks if initial effect is not satisfactory. Good informed consent explaining why other surgeries could not be carried out and all complications related to DLCP should be clearly mentioned. Kirti Singh: DLCP is a safe and efficient modality in controlling high IOP before attempting definitive surgery. However it alone is not sufficient to cause regression of NVI. In some scenarios it can be used as an alternative to GDD but do keep in mind that DLCP may need to be repeated. Tanuj Dada: Yes it can be done in situations where the patient is not systemically fit for surgery, refuses surgery once you have explained all the complications, the conjunctiva is extensively scarred (trabeculectomy cannot be done) and the patient cannot afford a glaucoma drainage device or the surgeon is not trained in this procedure. A 270 degrees DLCP may be done initially to minimize the risk of visual loss due to hypotony. DLCP should only be done once the cause of retinal ischemia has been treated. Suneeta Dubey: Adjunctive DLCP for immediate control of IOP and to buy time before definitive surgical management is done. Excessive laser treatment can lead to inflammation, hypotony and phthisis, so one needs to be conservative and treat only 2-3 quadrants at a time. Sirisha Senthil: Yes, there is a role for DLCP to take care of high IOP (although temporarily), until a definitive treatment is considered at a later date. Arun Narayanaswamy: DLCP has a definite role in the management of these situations and helps buy time for any definitive intervention. The key to using this effectively and to reduce your complications is to adopt a staged approach. Ensure that the patient is appropriately counselled on the risks and outcome. Summary (Sonal Dangda): Of late, role of DLCP has been explored in seeing eyes. It can be specifically attempted in cases with an inevitable delay in surgery, only to buy time. It can also be considered as a temporary measure in uncontrolled high IOP. Risk of phthisis and increased inflammation has to be guarded against by limiting the treatment area. Patient and relatives need to be properly counselled regarding risks and benefits prior to the procedure. 8,14,18 Sonal Dangda - Q. Role of combined surgery in cases with significant cataract (Figure 5) avoid or can be considered? Harsh Kumar: In case the patient has a significant cataract then one should definitely think of doing a combined surgery. The great advantage is that it will allow the retinal surgeon to perform a good PRP and visualize the retina for further management. However, if a person is not too confident of performing a combined surgery then a choice has to be made between the two depending upon the case scenario. If the pressures are high and are threatening the disc despite full medications, opt for the glaucoma surgery; but if the pressures are manageable, just do a cataract and allow the PRP to be performed. Depending upon the surgeon s experience, both, valve implant or trabeculectomy, can be combined with cataract surgery. Valves are easier to put in a combined surgery. Trabeculectomy has lesser chances of success, in such cases, and hence MMC should be used for a longer duration. Kirti Singh: Combined cataract surgery with tube shunts should be avoided wherever possible in cases of NVG, in order to avoid the risk of both bleed and inflammation; Del J Ophthalmol - Vol 26 No: 2 October-December

10 E-ISSN Ophthalmic Deliberations to get the IOP as close to normal as possible. Give preoperative mannitol (make sure patient doesn t have heart failure). Intra-operatively make sure to give extra time to MMC as the failure of trabeculectomy is higher in NVG. Try and preplace all flap sutures before entry. Make a slow decompression and make a side port before making the internal block. Fill the chamber with air which will prevent sudden decompression and bleed. If the air does not stay, use viscoelastics but remember to wash it out at the end and replace with air to give tamponade. Figure 5: Slit lamp photograph showing significant cataract in patient with NVG both scenarios being inimical to longevity of the filtering procedure. Tanuj Dada: Never combine a cataract surgery with trabeculectomy in NVG as there the outcome is very poor, with an early bleb failure. If combined surgery has to be performed then phacoemulsification with ciliary sulcus AGV is the best option (Avastin before surgery and PRP after it). Combined surgery is useful as it clears the media for definitive treatment of retinal ischemia i.e. PRP. Suneeta Dubey: Combined surgery is a better option when we are placing a GDD as it will create more space for the tube placement in AC, especially in cases with synechial angle closure. However, I would like to avoid a combined phaco-trabeculectomy. Sirisha Senthil: Combined surgery can be considered, since improving media clarity may also be essential for appropriate management of the posterior segment ischemia. Arun Narayanaswamy: A combined cataract surgery is best avoided. It can be considered in rare situations when the posterior segment view is severely compromised and one is unable to monitor and treat the posterior segment related issues. Summary (Sonal Dangda): Combined surgery although associated with greater chances of failure, might need to be considered in cases where cataract is significant enough to obscure posterior segment view and hinder PRP. If needed, better to combine with GDDs. 19 Sonal Dangda - Q. Any specific precautions which should be considered intra-operatively? Harsh Kumar: Please always take a consent explaining the particular case, chances of bleed, expulsive suprachoroidal haemorrhage, possibility of re-surgery and all routine trabeculectomy/gdd related complications. Always remember to take consent in the patient s/relative s own language because we get a lot of international patients nowadays. Make the eye as quiet as possible, give preoperative topical antibiotics and maximal medications Kirti Singh: The success of trabeculectomy is limited by the severe inflammation encountered with NVG eyes. In patients with NVG, VEGF concentration is increased in the aqueous humour and this in turn can trigger fibrosis. Moreover, fragile new vessels in iris and anterior chamber angle tend to bleed and lead to inflammation, hyphaema, and fibrinous reaction in the postoperative period which again has an adverse impact on the surgical success of glaucoma filtering surgery. Direct cauterization of peripheral iris before iridectomy may reduce risk of intraoperative bleeding and postoperative hyphaema. Creation of a small iridectomy or avoiding an iridectomy altogether in case of deep anterior chamber with no pupillary block has been recommended as other modifications. Another option is prior goniophotocoagulation of the area where inner sclerostomy will most likely be placed. Tanuj Dada: Give mannitol before surgery. Explain the risk of surgery and visual potential to the patient. Check the eye (don t operate the normal eye!). Ensure complete regression of NVI. There is increased risk of hyphaema in these cases and intraocular diathermy may be required. Suneeta Dubey: Always do slow decompression to avoid sudden hypotony. Utmost care has to be taken during tube placement as any trauma to the fragile new vessels can cause hyphaema; which can impair visualization during surgery as well as cause blood clots which can occlude the tube tip of a GDD. Sirisha Senthil: MMC to be used. Careful peripheral iridectomy avoiding traction on the root of the iris. If bleeders are present at the ostium, cauterise them or use air tamponade. Subconjunctival steroid to control post-op inflammation. May have to be combined with intravitreal anti-vegf, if there is persistence of new vessels. Instill cycloplegics drops on table, at the end of surgery. Arun Narayanaswamy: Most preparation to ensure uneventful surgery is pre-operative. All efforts to quieten the eye and low pre-operative IOP would reduce the intraop risk associated with decompression related bleeding. Also pre-operative or intra-operative laser photocoagulation of the peripheral iris in the area of iridectomy would help reduce risk of intra-operative bleeding. With regard to wound modulation, one may need to consider a slightly longer duration of MMC exposure. 147

11 Ophthalmic Deliberations ISSN Summary (Sonal Dangda): The IOP needs to be controlled preoperatively by intravenous mannitol (keeping contraindications in mind). Prior informed consent must be carefully taken. Sudden hypotony needs to be guarded against; slow decompression to be done. MMC exposure has to be for a slightly longer duration than usual. Air/viscoelastic tamponade, cauterisation of bleeders/ peripheral iris to be considered as chances of hyphaema are high. 20 Sonal Dangda - Q. Would the post-operative care be routine or do we need to be more specific? Harsh Kumar: Tell the patient to sit and sleep with head end elevated so as the bleed, if occurs, remains inferiorly and the air would keep pressing the wound area to give extra tamponade. Give more frequent steroids and also cycloplegics to suppress inflammation. Be alert for failure and see the patient regularly in the immediate post-op period. If the bleb does not form and the pressure elevates one should do bleb massage and also teach the patient to do it at home. At the earliest hint of too much massage being required, do a suturolysis or suture removal (in cases with a releasable suture). If hyphema is present, allow it some time for absorption but if it persists or aggravates, do an AC wash with warm BSS using small bimanual ports. Remember to leave an air bubble at the end of surgery. Kirti Singh: The most common cause of surgical failure in NVG cases is related to the progression of underlying disease, which needs to be controlled. Post-operative topical steroids need to be given minimal for 8 weeks to control post-op scarring and addition use of topical NSAID can be considered to reduce macular edema. Bleb scarring is more common in NVG cases, therefore a more frequent follow-up and requirement for additional interventions like needling and/or repeat trabeculectomy should be kept in mind. Tanuj Dada: Post-operatively these patients can have a fibrinoid reaction and need aggressive steroid and cycloplegic therapy. There is high risk of failure, so they need close observation. MMC application over the bleb, bleb massage, and bleb needling with 5 FU etc. may be needed on follow-up. Additionally the retinal condition needs to be monitored by a retina specialist. Never forget to carefully examine and treat the fellow eye. Suneeta Dubey: Intensive topical steroid therapy with cycloplegics has to be given post-operatively for a longer time to control the inflammation. Sirisha Senthil: Increase the steroid frequency Cycloplegics Additional laser if pending, owing to corneal edema prior to glaucoma surgery Post-operative visits to be more frequent, as per need to monitor the IOP and bleb Arun Narayanaswamy: I adopt a more aggressive steroid regimen in cases with NVG. The follow-up is also more frequent so as to consider anti-metabolite injections depending on the bleb morphology. More recently, in cases that have had a GDD, I continue aqueous suppressants post-operatively as it has been shown to be beneficial in thwarting the hypertensive phase. Avnindra Gupta: Post-operative laser photocoagulation is not a contraindication and can be started as early as day 1. Summary (Sonal Dangda): Post-operatively aggressive cycloplegic and steroid therapy needs to be prescribed for a longer duration Cases in which PRP has to be completed or augmented can be taken up as early as day 1. Follow-up visits need to be more frequent initially; also closely monitor the other eye. Cite This Article as: Dangda S, Kumar H, Singh K, Dada T, Dubey S, Senthil S, Narayanaswamy A, Gupta A. Neovascular Glaucoma. Delhi J Ophthalmol 2015;26: Acknowledgements: Rohan Chawla, Sunil Choudhary, Neha Midha Date of Submission: Date of Acceptance: Conflict of interest: None declared Source of Funding: Nil Quick Response Code Access this article online References Website DOI 1. Sivak-Callcott JA, O Day DM, Gass JD, Tsai JC. Evidencebased recommendations for the diagnosis and treatment of neovascular glaucoma. Ophthalmology 2001; 108: Hayreh SS. Neovascular glaucoma. Prog Retin Eye Res 2007; 26: Flanagan DW, Blach RK. Place of panretinal photocoagulation and trabeculectomy in the management of neovascular glaucoma. Br J Ophthalmol 1983; 67: Browning DJ. Risk of missing angle neovascularization by omitting screening gonioscopy in patients with diabetes mellitus. Am J Ophthalmol 1991; 112: Laatikainen L. Preliminary report on effect of retinal panphotocoagulation on rubeosis iridis and neovascular glaucoma. Br J Ophthalmol 1977; 61: Avery RL. Regression of retinal and iris neovascularization after intravitreal bevacizumab (Avastin) treatment. Retina 2006; 26: Euswas A, Warrasak S. Long-term results of early trabeculectomy with mitomycin-c and subsequent posterior segment intervention in the treatment of neovascular glaucoma with hazy ocular media. J Med Assoc Thai 2005; 88: Tsai JC, Bloom PA, Franks WA, Khaw PT. Combined transscleral diode laser cyclophotocoagulation and transscleral retinal photocoagulation for refractory neovascular glaucoma. Retina 1996; 16: Iliev ME, Domig D, Wolf-Schnurrbursch U, Wolf S, Sarra GM. Intravitreal bevacizumab (Avastin) in the treatment of Del J Ophthalmol - Vol 26 No: 2 October-December